1. Field of the Invention
The present invention relates to a camera capable of magnetically and photographically recording information of each picture frame on a photographic film.
2. Description of the Related Art
There are known various types of cameras having a built-in information recording device for magnetically or photographically recording information such as a photographing date, a photographing format, and exposure data on a photographic film at the time of photographing. In the case of magnetic recording, a magnetic head is used, and in the case of photographic recording, a record/display unit is used. The record/display unit is formed by a liquid crystal device (LCD) or light emitting diodes (LED), both in the order of 60 segments. For example, in order to record a photographing date on a photographic film, not only a clock circuit but also a monitor display unit made of an LCD or LEDs is required to check whether the time of the clock circuit is correct. Other circuits are also required, such as a circuit for converting information into a signal suitable for the recording type, a timing circuit used for writing information synchronously with a film advance, and a controller for the sequence control of each circuit. An information recording device has a huge number of lead wires interconnecting such circuits. It is therefore desirable to mount these circuits on one circuit board, when considering the simplicity of manufacturing and the effectiveness in space.
In the case of recording information regarding a picture frame at the area near the frame, if the record area is not set at a high precision, an error may occur when reading the information by a photographic print system. Therefore, an approach has been used wherein a magnetic head or LED is driven while monitoring the film advance amount based on the detection of perforations. In this case, not only a photo sensor for detecting a perforation is required, but also the relative position between the photo sensor and the magnetic head or LED is required to be set precisely.
In the case of magnetic recording in synchronism with a film advance, it is necessary to stabilize the contact condition (head touch) between the magnetic recording layer of a film and the magnetic head, because magnetization of the layer otherwise would become insufficient, resulting in a possible read error. In order to maintain the head touch constant, it is advantageous to set correctly the position of the magnetic head relative to the film pressure plate which mainly regulates the position of the film.
Assuming that the above information recording is to be performed, the system structure of a camera becomes complicated should the film advance control and the information recording control be performed by separate control circuits. In addition, it is necessary to use long lead wires on which electrical noises are likely to be superposed.
It is desired to make compact the record/display unit and the information recording device. It is also necessary to precisely set the position of an information recording element relative to a perforation sensor and a film pressure plate and to set the record areas on a photographic film at regular positions. With conventional information recording devices, these factors have been considered insufficiently, leading to a wasteful assembly space, irregular information record areas, and data read errors.